SEPP output transformer

pat49hk · 30th April 2009, 04:10 PM

Dear All,

I found a SEPP circuit from an old magazine of year 1966 as Fig-1 shown. It was using an output transformer which has two groups of primary windings. Can anybody explain what is the different if using a single winding transformer as Fig-2 and the advantages and disadvantages in comparison?

Thanks

Patrick

pat49hk · 30th April 2009, 04:12 PM

Fig-2

Geek · 30th April 2009, 10:44 PM

Fig. 1 shows 2 windings, each with screen current drawn through it in opposite phase, therefore the DC cancels.

AC wise, it's the same as Fig. 2.

But there's a hair bit of DC in fig. 2 that appears to be some FB method to the driver tube.

Cheers!

pointy · 1st May 2009, 11:19 AM

you may be able to get a transformer with a centre tapped primary and then cut at the centre tap so you have the two half's.

(like them diy's would do in thems days)

pat49hk · 2nd May 2009, 02:20 AM

Dear Geek,

Thank you for your response. Can you tell me more details of the transformer winding topology of both?

Dear Pointy,

Thank you for your advice, I intend to wind the transformer myself. Any idea can tell?

Regards

Patrick

Geek · 2nd May 2009, 07:21 AM

Hi Patrick,

Quote:

Originally posted by pat49hk
Dear Geek,

Thank you for your response. Can you tell me more details of the transformer winding topology of both?

Not any more than I have really... I haven't studied or explored parafeed transformers that much, outside of making a pair for a headphone amp that used neither of these topologies. So I shall derfer to someone who may know more.

Cheers!

pat49hk · 2nd May 2009, 09:34 AM

Dear Geek,

However, thanks a lot.

Regards

Patrick

the_manta · 2nd May 2009, 09:45 AM

Hi Patrick !

I did a similar project.

Here are some pics about it.

regards, Simon

Shoog · 2nd May 2009, 09:57 AM

That parafeed cap seems very small. When i messed about with parafeed I always used something around 4uf.

What power where you getting?

Looks like one of my messy builds.

Shoog

singh santa · 2nd May 2009, 07:20 PM

[QUOTE]Originally posted by pat49hk
[B]Dear All,

I found a SEPP circuit from an old magazine of year 1966 as Fig-1 shown. It was using an output transformer which has two groups of primary windings. Can anybody explain what is the different if using a single winding transformer as Fig-2 and the advantages and disadvantages in comparison?

Hi,
Fig1 is right for pentodes fig 2 is only work for triode.the two resistor of g2 will eat most of the output power.
Cheers!
Singh

2nd May 2009, 07:20 PM	#10
singh santa diyAudio Member Join Date: Mar 2009	Re: SEPP output transformer [QUOTE]Originally posted by pat49hk [B]Dear All, I found a SEPP circuit from an old magazine of year 1966 as Fig-1 shown. It was using an output transformer which has two groups of primary windings. Can anybody explain what is the different if using a single winding transformer as Fig-2 and the advantages and disadvantages in comparison? Hi, Fig1 is right for pentodes fig 2 is only work for triode.the two resistor of g2 will eat most of the output power. Cheers! Singh

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30th April 2009, 10:44 PM	#3
Geek diyAudio Member Join Date: Sep 2004	Fig. 1 shows 2 windings, each with screen current drawn through it in opposite phase, therefore the DC cancels. AC wise, it's the same as Fig. 2. But there's a hair bit of DC in fig. 2 that appears to be some FB method to the driver tube. Cheers!

1st May 2009, 11:19 AM	#4
pointy diyAudio Member Join Date: Mar 2009	you may be able to get a transformer with a centre tapped primary and then cut at the centre tap so you have the two half's. (like them diy's would do in thems days)

2nd May 2009, 02:20 AM	#5
pat49hk diyAudio Member Join Date: Sep 2005	Dear Geek, Thank you for your response. Can you tell me more details of the transformer winding topology of both? Dear Pointy, Thank you for your advice, I intend to wind the transformer myself. Any idea can tell? Regards Patrick

2nd May 2009, 09:34 AM	#7
pat49hk diyAudio Member Join Date: Sep 2005	Dear Geek, However, thanks a lot. Regards Patrick

2nd May 2009, 09:45 AM	#8
the_manta diyAudio Member Join Date: Nov 2006 Location: Munich, Bavaria	Hi Patrick ! I did a similar project. Here are some pics about it. regards, Simon

2nd May 2009, 09:57 AM	#9
Shoog diyAudio Member Join Date: Aug 2002 Location: Eire	That parafeed cap seems very small. When i messed about with parafeed I always used something around 4uf. What power where you getting? Looks like one of my messy builds. Shoog

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